Study of effect of sulfate-reducing bacteria on corrosion interface between Q235 steel and sea mud

The corrosion behavior of Q235 steel influenced by sulfate-reducing bacteria (SRB) in sea mud was investigated from the point of view of corrosion interface for the first time by microbiological technique, metallographic microscope and electronic probe microanalyzer (EPMA). The results show that the original corrosion products, iron (hydr) oxides, gradually transform to low-sulfur and high-sulfur iron sulfides. For the crystal defect and loose structure of the latter, the diffusion of Fe2+ and penetration of aggressive ions can not be prevented, which accelerates the corrosion process. Furthermore microbial activity and transformation of corrosion products enable the formation and extension of pitting corrosion, which occurs and extends along the grain boundary and pearlite area.